Citizen Henry A. Kissinger finally spoke his long-awaited word yesterday on the SALT II treaty upon which Secretary of State Henry A. Kissinger left so strong an imprint of paternity.

He did not rush to embrace his political foundling.Instead, he delivered a message to the Senate Foreign Relations Committee, current forum of the SALT debate, sprinkled with words of Spenglerian gloom on the American-Soviet strategic balance and exhortations to higher U.S. military spending.

Beneath his carefully crafted reservations, however, Kissinger did supply the endorsement for the SALT II pact for which the Carter administration had been sorely hoping.

The performance led proffessional semanticist Sen. S.I. Hayakawa (R-Calif.) to exclaim admiringly to Kissinger on "the texture of your thought, the stately procession of your sentences and paragraphs."

In his testimony Kissinger drew a picture of a United States menaced by the "geopolitical offensive" of a Soviet Union now emboldened by the prospect of strategic superiority in the early 1980s. It was a theme that often had echoed from the lips of treaty opponents in the Senate chamber the last few weeks.

It was a state of affairs for which he said he sought to cast no blame, but could be traced to the military doctrines of the 1960s (Kennedy-Johnson years), the political backlash of the Vietnam war and the Carter administration's "unilateral" cancellations or delays in strategic weapons systems started in the Nixon years.

Doggedly, Kissinger pressed his version of history through the challenges of Democratic interrogators such as Foreign Relations Chairman Sen. Frank Church (D-Idaho) and Sen. Joseph R. Biden Jr. (D-Del.).

Church reminded Kissinger of his admonition in 1976 against "those who paint dark vistas of looming U.S. inferiority" when he, as secretary of state, was still pressing for acceptance of the SALT II principles he and president Ford had negotiated at Vladivostok.

"What has changed" Church asked after Kissinger had painted dark vistas of Soviet strategic superiority. Kissinger answered that what had changed was the abandonment of the military program he and Ford were proposing as well as the acceleration of Soviet technology.

This provoked new challenges from Church and Biden.

One major ironay of yesterday's performance is that Kissinger found himself jousting with the advocates, rather than the opponents, of the SALT process. In previous years when he, as secretary of state, was pressing the SALT cause, these were the senators who formed his core of supporters and admirers.

Also, the same Henry Kissinger who when in power deplored congressional enroachment in the foreign policy process yesterday proposed periodic two-year Senate reexaminations of the treaty as well as any future SALT negotiations from the standpoint of Soviet global political behavior. It was a proposal by Citizen Kissinger that Secretary Kissinger would undoubtedly have found abhorrent.

The most vexing moments for Kissinger came when Sen. Paul S. Sarbanes (D-Md.) tried to press him on the point of whether he would have recommended signing the treaty now before the Foreign Committee.

"This is a difficult question . . . er, er, answer," replied the treaty's chief architect. Sarbanes repeatedly pressed and Kissinger hedged.

Finally, under Sarbanes' battering attempt, Kissinger said, "Yes, I probably would have signed the treaty and presented it to the Senate." Then came the condition: "But I would have simultaneously asked for military changes."

Ambivalence was the political keynote of Kissinger's overall testimony.

Within the course of his appearance yesterday he said no, that he would not sign the treaty unless it were accompanied by higher military spending and other conditions. He also said yes, he would sign the treaty if his terms were met. The "no" was delivered to Sen. Jesse A. Helms (R-N.C.), an opponent of the treaty. The "yes" was uttered to Sarbanes, a supporter.

In fact President Carter has already accepted a higher level of military spending - 3 percent beyond inflation - to meet NATO needs. The commitment was reaffirmed Monday by Secretary of State Cyrus R. Vance before the Senate Armed Services Committee.

Kissinger carefully chiseled his reservations so that none would require renegotiation of the treaty, a principal objective of the "killer" amendments being proposed by opponents of SALT II.

Kissinger kept his testimony from the Foreign Relations Committee until shortly before his appearance yesterday, a departure from Senate convention. But when it was all over, the administration's SALT strategists were understandably satisfied. They had every reason to be.

Despite Kissinger's "reservations" and ambiguities, they knew that he had come down ummistakably for ratification - albeit as the Republican Party's chief foreign policy spokesman and a potentially influential adversary in the 1980 presidential campaign.

However complex and tortuous his arguments, Kissinger in the end had to acknowledge his paternity of the SALT II treaty. He also had to act accordingly. CAPTION: Picture 1, HENRY A. KISSINGER . . . foresees "very grave dangers"; Picture 2, Henry A. Kissinger: "Yes, I probably would have signed the treaty . . .", UPI